The motors of aircraft are generally integrated within a structure, called in what follows a nacelle, connected by connection means to the aircraft, particularly by a mast to the wing.
This nacelle has several functions, particularly those of regulating and controlling the movements of the air about and in the motor so as to optimize the aerodynamic flows, to protect the motor from external elements, to attenuate sonic nuisance, to ventilate the internal zones, to take part in the distribution of mechanical forces of the motor and if desired to support systems for pressure reversal.
Finally, the nacelle should permit the routine maintenance and upkeep of the motor and its components.
To this end, the nacelle comprises, at the level of its external surface, an opening permitting access to the interior of the nacelle and a movable part adapted to occupy at least two positions, a first so-called closed position in which said movable part is disposed in prolongation of the external surface of the nacelle so as to close said opening, and a second position in which it frees at least partially the opening.
In what follows of the description, the movable portion is called a door.
In FIGS. 1 and 2, there is shown at 10 a nacelle connected by a mast 12 to a wing 14, said nacelle comprising a front air inlet 16 and a lateral fuselage 18 with a longitudinal axis 20. The nacelle 10 comprises at least one opening 22, preferably two disposed on each side, on opposite sides of the mast 12, adapted each to be closed respectively by a door 24.
According to the prior art, each door 24 is articulated relative to the upper edge of the opening 22 and pivots about an axis 26 substantially parallel to the axis 20 of the nacelle, disposed near the mast 12.
As a supplement, locking means are provided to hold the doors 24 closed. According to one embodiment, the lower ends of the doors are connected when these latter are in closed position, by bolts (not shown).
Preferably, as shown in FIG. 2, two props 28 are provided to hold each door in open position.
Even if this type of door is relatively simple and permits easy access to the elements mounted in the lower portion of the motor, it does not give complete satisfaction for the following reasons:
The positioning of the door in the open position facing the opening at the level of the medial portion of the upper portion, does not favor access to these parts. Thus, the operators must slide between the door and the motor first of all lowering themselves to pass below the panel of the door, taking the risk of injuring themselves against the edges of the door.
However, this manner of opening does not permit ensuring optimum safety to the operators. Thus, even if they are held by props, the doors can close abruptly, especially due to gusts of wind, and injure the operator disposed between the door and the motor.
As shown in FIG. 1, the upper portions of the existing articulated doors have a large wind profile even though the doors are dimensioned to resist wind gusts of the order of 100 Km/h. However, these stresses in the open position are much greater than those to which the doors are subjected in closed position. Thus, the doors are dimensioned for unusual use.
Finally, for a door of large size, its manipulation can be difficult, the operator having to raise said doors to effect the opening. In excess of certain dimensions, it is necessary to provide an onboard system for assisting opening and closing, complicating the design and increasing the installed weight of the aircraft.
Moreover, certain installation of propulsive systems, particularly of large size, can be relatively near the other portions of the aircraft, with configurations that can give rise to interference between the door in open position and the air foil or the nose of the attack edge in deployed position, or any other fixed or movable surface. It is necessary in these cases to provide protection which add a further increase of weight and complexity to the aircraft.
Also, the present invention seeks to overcome the drawbacks of the prior art by providing an articulation device for a door of an aircraft nacelle, permitting freeing in an optimum manner the opening and rendering the intervention of the operators more certain, and possibly lightening the nacelle.